The minimum stimulation needed to detect a particular stimulus 50 percent of the time

TOLERANCE

The diminishing effect with regular use of the same dose of a drug, requiring the user to take larger and larger doses before experiencing the drug's effect

INFORMATION PROCESSING

To file away memories; dreams may help sift, sort and fix the day's experiences in our memory

PARALLEL PROCESSING

The processing of several aspects of a problem simultaneously; the brain's natural mode of information processing for many functions including vision. Contrasts with the stwp-by-step processing of most computers and of conscious problem solving. Brain cell teams process combined information about color, movement, form and depth

Performing well-learned tasks automatically, changing our attitudes and reconstructing our memories with no awareness of doing so, registering and reacting to a vast number of stimuli we do not consciously perceive

A sleep disorder characterized by high arousal and an appearancy of being terrified; unlike nightmares, night terrors occur during Stage 4 sleep, within two or three hours of falling asleep, and are seldom remembered

DEPTH PERCEPTION AND THE VISUAL CLIFF EXPERIMENT

Depth perception is our ability to see objects in three dimensions, which lets us judge distance. The visual cliff and other research demonstrates that many species perceive the world in three dimensions at, or very soon after, birth